"This is the talk of a military strongman, not of a democratic mayor," Cachalia said in a statement.

"He used a platform yesterday at the Chris Hani Memorial Lecture, and an Ekurhuleni-branded event, to make these threats and as such he must be investigated in his official capacity."

The DA was considering laying criminal charges against him for incitement to violence and intimidation.

Ekurhuleni spokesperson Gugu Didima said the mayor's office had not received any correspondence about the matter having been referred to the ethics committee. The office would respond if it was received.